Sugary Drinks Tied to Obesity, Type 2 Diabetes

Study finds risks rise along with soda, fruit punch consumption

Please note: This article was published more than one year ago. The facts and conclusions presented may have since changed and may no longer be accurate. And "More information" links may no longer work. Questions about personal health should always be referred to a physician or other health care professional.

The study adds new fuel to the debate on the sources of weight gain and their ultimate impact on the ever-growing diabetes epidemic. Both the study's authors and its critics agree that caloric intake is crucial to the problem.

Type 2 diabetes and its partner, obesity, are among the top public health crises in the world today, with over 17 million Americans suffering from type 2 diabetes.

According to the study authors, soft drinks are the leading source of added sugars in the U.S. diet. Moreover, the increase in the prevalence of diabetes and obesity has coincided with a 61 percent increase in the consumption of soft drinks by adults, and a doubling in consumption by children and adolescents between the late 1970s and the mid-1990s.

This prospective study looked at over 91,000 women participating in the ongoing Nurses' Health Study II, all of whom were free of diabetes and other major chronic diseases in 1991. During the 8-year course of the study, however, 741 cases of type 2 diabetes were confirmed. The work appears in the Aug. 25 issue of the Journal of the American Medical Association.

Weight gain over two four-year periods (1991-1995 and 1995-1999) turned out to be highest among women who increased the number of sugar-sweetened soft drinks they consumed from one or fewer per week to one or more per day. Women who increased their consumption of fruit punch also gained more weight than those who decreased their consumption.

In this study, women who drank high levels of sugar-sweetened soft drinks also smoked more, were less physically active, and had lower intakes of fiber and magnesium.

Even after adjusting for other factors, women who consumed one or more sugar-sweetened soft drinks per day had an 83 percent increased risk of developing diabetes compared to those who drank less than one per month. Women who drank one or more fruit punches a day had twice the risk for diabetes as women who drank less than one a month. Diet cola and fruit juice was not associated with type 2 diabetes.

Weight gain was only one way that these beverages seemed to increase the incidence of type 2 diabetes, according to the researchers.

"About half of the increase in the risk of type 2 diabetes is due to the weight gain that occurs with sugar-sweetened beverages, but the other half may be related to the fact that these sugars are rapidly absorbable," said Dr. JoAnn Manson, a study co-author. "High-fructose corn syrup leads to fast and dramatic rises in glucose and insulin levels, and that can lead to insulin resistance and the development of type 2 diabetes," added Manson, chief of preventive medicine at Brigham and Women's Hospital in Boston and a professor of medicine at Harvard Medical School.

There may also be an issue of how satisfied and full these beverages make consumers feel. Women who drank large amounts of these beverages also tended to eat more, although it was not entirely clear why. "Drinking something that has calories is not going to fill you up," said Elisabetta Politi, nutrition manager at Duke University's Diet and Fitness Center in Durham, N.C. "That's what we need to be vigilant about. It's definitely a good recommendation for people struggling with weight control to not consume caloric drinks."

The findings drew criticism from the soft drink industry. "Frankly, I think the conclusions are scientifically unsound," said Richard Adamson, vice president for scientific and technical affairs at the American Beverage Association. "It has nothing to do with a particular macronutrient. Basically, it's calories in and calories out."

Manson agreed with the last part of that statement. "I agree that it's calories in and calories out in terms of weight gain. Sugar-sweetened soft drinks are not single-handedly causing the epidemic of obesity and type 2 diabetes, but they are important contributors," she said. "Sedentary lifestyle, high intake of fast foods, large portion sizes, high calorie intake overall are very important factors, [but] there is still an independent contribution for sugar-sweetened beverage intake."